Ohioan John Mauchly and J. Presper Eckert designed the Electronic Numerical Integrator and Computer, which is better known as ENIAC. Construction of ENIAC began in 1944. It took workers eighteen months to complete the machine, and it cost over 500,000 dollars. ENIAC weighed over thirty tons and consisted of 17,468 vacuum tubes, seventy thousand resistors, five million soldered joints, ten thousand capacitors, six thousand manual switches, and 1,500 relays. The computer covered 1,800 square feet of floor space. ENIAC used approximately 160 kilowatts of electricity, causing Philadelphia, Pennsylvania, where the computer was located, to experience brownouts when the machine was in operation.

ENIAC was not the first computer in world history. It did, however, dramatically improve computing technology. Antiquated by modern computing standards, for the time period, ENIAC was an incredible machine. In a single second, it could perform five thousand additions, thirty-eight divisions, or three hundred multiplications. It was one thousand times faster than calculators of this time period.

ENIAC remained in operation until October 2, 1955. By this time, ENIAC had become outdated. Mauchly, Eckert, and others had already designed more powerful computers. ENIAC is currently owned by the Smithsonian Institution.